The present invention relates to a heat exchanger (oil cooler) for cooling oil with water and particularly to a so-called housing-less type oil cooler formed by stacking plate members together.
Japanese Patent Unexamined Publication JP-A-7-286786 discloses such housing-less type heat exchanger (oil cooler), as shown in FIGS. 6-8 of the present application. As shown in FIG. 6, this heat exchanger has a core portion 51. This core portion 51 is reinforced with upper and lower reinforcing plates 53, 55 (made of aluminum). The upper reinforcing plate 53 is covered with a cover member 57, and a void space 59 is provided between the cover member 57 and the upper reinforcing member 53. A collar member 63 is disposed at a central portion of the core portion 51 for receiving an attaching bolt 61 therethrough. An attaching member 65 is disposed under the lower reinforcing plate 55 for attaching the heat exchanger to an automatic transmission. As shown in FIG. 7, each of the upper reinforcing plate 53 and the cover member 57 is provided with through holes for receiving therethrough a cooling water inlet pipe 67 and a cooling water outlet pipe 69. The core portion 51 is formed of first and second plates 71 and 73 (made of aluminum having thereon a cladding of a brazing material) alternately stacked together such that cooling water chambers 75 and oil chambers 77 are alternately formed between these plates 71, 73. As shown in FIG. 6, adjacent oil chambers 77 are communicated with each other through a pair of oil passages 79a and 79b, which are symmetrically arranged about the collar member 63 disposed at the central portion. Furthermore, inner fins 81 are received in the oil chambers 77. In contrast, as shown in FIG. 7, adjacent water chambers 75 are communicated with each other through a pair of cooling water passages 83, which are symmetrically arranged about the collar member 63. The oil passages 79a and 79b are partly blocked by blocking plates 71A, 73A. As shown in FIG. 6, an oil inlet pipe 85 is inserted deep in the core portion 51 by passing it from a first side (the side of the cover member 57) through the cover member 57, the upper reinforcing plate 53, the 9 oil passage 79a and the blocking plates 71A and 73A. The oil inlet pipe 85 is formed with upper and lower projections 85a and 85b. The upper projection 85a is brazed to the cover member 57 to sealingly close the through hole of the cover member 57. The lower projection 85b is sealingly brazed to the blocking plate 71A. The oil inlet pipe 85 has a diameter that is substantially smaller than that of the oil passage 79a, except at the position of the blocking plates 71A and 73A, such that an annular space is provided between the oil inlet pipe 85 and the outer periphery of the oil passage 79a. The oil is allowed to flow through the annular space as shown by the arrows of FIG. 6. An oil outlet pipe 87 is inserted in the core portion 51 by passing it through the cover member 57 and the upper reinforcing plate 53. The oil outlet pipe 87 is formed with (a) a projection 87a sealingly brazed to the cover member 57 and (b) and an end sealingly brazed to the upper reinforcing plate 53. As shown in FIG. 6, the oil is introduced into a lower portion of the core portion 51 from the oil inlet pipe 85. Then, it is allowed to flow in the core portion 51 in a meandering manner by the provision of the blocking plates 71A and 73A, as shown by the arrows of FIG. 6. After that, it is allowed to flow out of the core portion 51 into the oil outlet pipe 87. In contrast, as shown in FIG. 7, the cooling water is introduced into the core portion 51 from the cooling water inlet pipe 67. Then, it is allowed to flow through cooling water passages 83. Each cooling water chamber 75 is filled with the cooling water, thereby conducting a heat exchange between the heated oil and the cooling water. After this heat exchange, the water is allowed to flow into the cooling water outlet pipe 69 from the core portion 51. As shown in FIG. 8, the heat exchanger 99 is attached to an automatic transmission 91. In fact, this transmission 91 is formed with threaded projections 93. An attaching base 95 is fixed to the threaded projections 93 by threadedly engaging bolts 97 with the threaded projections 93. The attaching base 95 is formed at center with a threaded hole 95a. The attaching bolt 61 is inserted into the collar member 63 of the core portion 51 and then threadedly engaged with the threaded hole 95a, thereby attaching the heat exchanger 99 to the automatic transmission 91. Furthermore, oil inlet and outlet pipes 101 and 103 of the transmission 91 are respectively connected with the oil inlet and outlet pipes 85 and 87 of the heat exchanger 99. It is possible to turn the oil flow direction by the provision of the blocking plates 71A and 73A. As mentioned above, the oil inlet pipe 85 is inserted deep in the core portion 51 in order to achieve an oil flow in a meandering manner. This makes the heat exchanger""s piping structure very complicated.
It is therefore an object of the present invention to provide a heat exchanger that is capable of achieving an oil flow in a meandering manner without inserting a pipe member deep in a core portion of the heat exchanger.
It is another object of the present invention to provide a heat exchanger that is capable of providing a superior heat exchange between oil and cooling water with a relatively small number of parts and a relatively simple construction.
According to the present invention, there is provided a heat exchanger for cooling oil with water, comprising:
a plurality of plates stacked together to form a core portion of said heat exchanger such that a plurality of oil chambers for receiving the oil and a plurality of water chambers for receiving the water are alternately formed between said plates, said water chambers being communicated with each other through first and second water passages;
a first wall portion for defining a through hole in said core portion, said through hole allowing the oil to flow therethrough and having first and second ends at first and second sides of said core portion respectively, said first end being one of an inlet for allowing the oil to flow into said core portion and an outlet for allowing the oil to flow out of said core portion;
a second wall portion for defining a first oil passage in said core portion, said first oil passage extending between said first and second sides of said core portion to communicate with said oil chambers, said first oil passage having first and second ends at said first and second sides of said core portion respectively, said first end of said first oil passage being the other of said inlet and said outlet;
a third wall portion for defining a second oil passage in said core portion, said second oil passage extending between said first and second sides of said core portion to communicate with said oil chambers; said second oil passage having first and second ends at said first and second sides of said core portion respectively,
a first blocking plate for blocking a part of said first and second oil passages such that a flow of the oil is turned from one of said first and second oil passages to the other of said first and second oil passages; and
a first cover member for sealingly covering said second side of said core portion, said first cover member having an oil passage extending between said second end of said through hole and at least one of said second end of said first oil passage and said second end of said second oil passage.